Motor control.



PATENTED AUG. 16, 1904.

J. 1). IHLDBR. MOTOR CONTROL.

APPLICATION FILED MAY 5, 1902.

N0 MODEL.

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UNITED STATES PATENT OEEicE.

JOHN D. IHLDER, OF YONKERS, NEIV YORK, ASSIGNOR TO OTIS ELEVA- TORCOMPANY, OF EAST ORANGE, NEIV JERSEY, A CORPORATION OF NEW JERSEY.

MOTOR CONTROL.

SPECIFICATION forming part of Letters Patent No. 767,691, dated August16, 1904,-

Application filed May 5, 1902. Serial No. 106,072. (No model.)

To all 1071,0717, it may concern:

Be it known that I, J oHN D. IHLDER, a citizen of the United States,residing at Yonkers, in the county of lVestchester and State of NewYork, have invented certain new and useful Improvements in MotorControl, of which the following is a specification.

My invention relates to motor control; and its objects are primarily toenable an electric motor to be automatically controlled in a simple andconvenient manner which reduces the liability of injury to the motor andprevents the starting-current from rising beyond a predetermined amount.

Further objects of my invention will hereinafter appear; and to theseends my invention consists in the system of motor control devised forcarrying out the above objects and having the general mode of operationsubstantially as fully described and shown in the accompanyingspecification and drawings, in

which Figure l is a diagrammatic view showing circuits and apparatusembodying one form 2 5 of my invention, and Fig. 2 is a diagrammaticview showing a modified form of my invention.

Referring to the drawings, A represents a motor, which may be of anysuitable type, but

shown in this instance as a shunt-wound motor adapted to be connected incircuit with the supply-mains (indicated by and and provided with aseries field-winding B and a shunt-field C, the shunt-field beingconnected 3 5 to the mains at the points a and 6. A suit able switch Dis arranged to control the admission of current to the motor-armature,and the throwing of the switch-lever 0 into contact with contacts (Z and6 will first complete the circuit of the electromagnet E, connectedacross the mains and controlling contacts f in the mainarmature-circuit. The energizing of magnet E closes contacts f andcompletes the circuit to the motor through resistances F and G and theseries field-winding B, which also includes, preferably, a portion ofthe starting resistance H for purposes of regulating. The completion ofthe armature-circuit throws the full -line potential on magnet 1, shownconnected across the line from a point to the switch D, causing magnet Ito actuate its core 1: and close circuit between contacts 1 and 5 andthe insulated contact 6 and 7 on the core, thereby short-circuiting aportion of resistance F and completing a circuit through theshunt-winding /t of the doubly-wound magnet 1. The doubly-wound magnets1, 2, and 3 are assumed to be diiierentially wound, being provided withshunt-windings it, connected in parallel to each other and in shunt tothe main line, and also provided with windings 'in series with the line,the series windings being of insuflicient strength,however, to moveacore Z; even with maximum current. After magnet I has closed itscontacts and short-circuited a portion of resistance F the current willhave increased sufficiently to start the motor under all loads, andalthough but one magnet I is illustrated for the sake of simplicity inthe diagram of Fig. 1 any desired number of magnets I may be used toshort-circuit the resistance F in a series of steps to admit the maximumpermissible strength of starting-current. The starting of the motor cutsdown the armature-current and the strength of the series winding j ofmagnet 1, while the shunt-winding lb of said magnet gradually comes upto maximum strength due to the diflerence of potential between thepoints Z and a on the line between which the shunt-winding is connected,this difference of potential not being quite the fullline potential,since the point Z is taken between the resistance F and the motor, whichis the preferable arrangement, because the fall of potential through theresistance F aids in regulating the magnet 1, the fall of potentialbeing greater with the maximum current which causes the closing of thecontacts of magnet 1 than with a reduced current. As the currentdecreases and as the resistance F decreases with a plurality of suchstarting-magnets I or with the one magnet shown the shunt-coil ii ofmagnet 1 becomes strengthened, while the series coil jbecomes weakeneduntil a point is reached where the core I: is actuated to close circuitbetween contacts 8 and 9 and insulated contacts 10 andll on the core,thereby short-- circuiting more of the starting resistance F andcompleting the circuit of the shunt-coil h of magnet 2. Theshort-circuiting of resistance F again increases-the current to amaximum, from which it is reduced by the further increase of armaturespeed, thus repeating the operation for magnets 2 and 3 as described formagnet 1, until finally circuit is closed between contacts 12 13 and 1415 of magnet 2 and contacts 16 17 and 18 19 of magnet 3, whereby all ofthe resistance and the series field-winding B are short-circuited.

It will be seen that as the magnets 1, 2, and 3 operate the serieswindings 'j are short-circuited in turn, and when magnet 3 operates toclose contacts 16 and 18 a circuit is completed to a third winding onmagnet 3 and to a magnet g, the circuit of magnets 19 and 9 beingconnected, as shown in this instance, across the line. Coil 2 operatesas a holdingcoil to maintain contacts 16 17 and 18 19 closed, and magnetq actuates contacts 20 to break the circuit of all the shunt-windingsIt, so that they do not consume current after the motor has started.

According to my invention the current cannot rise beyond a predeterminedamount, for any increase of current beyond the predetermined amount instarting so strengthens a series winding j that the operation of cuttingout resistance does not continue until the current has again reduced tothe desired amount. In other words, my apparatus is so constructed thatthe amount of starting-current which can be admitted is limited, forwhen the startingcurrent rises beyond a predetermined amount theoperation of cutting out resistance will be suspended.

To stop the motor, the lever c is moved to break circuit with contacts(Z and 6, contact d being longer than 6, so that circuit is broken withcontact 0 first. thus breaking the circuit of magnet q first andthrowing the resistance back into circuit before magnet E is denergizedto break the armature-circuit.

It is not necessary that each shunt-winding 72, should have its circuitseparately controlled, as described in connection with Fig. 1, nor thatthere should be a magnet I or magnets provided for the preliminaryoperation of admitting. the maximum starting-current, for the maximumstarting-current may be admitted at once on the first step, if desired,as provided for in Fig. 2.

In Fig. 2 the shunt magnet-windings it of magnets 1, 2, and 3 are shownin series with each other and connected to the line in such manner thatcircuit through them is always completed when switch D is closed. Theseries windings 'of these magnets are arranged in the same manner asbefore, and this whole construction requires a more exact adjustmentthan that shown in Fig. 1 to obtain the same operation. The shunt andseries windings on --may be wound to different strengths with thearmatures 21, 22, and 23 arranged at the same distances from the coresk. In this latter case the shunt-windings it may decrease in strengthfrom magnets 1 to 3, or else the series windings j may increase instrength from magnets 1 to 3, as may be desired, so that magnet 1 alwaysoperates to attract its armature on less magnet strength than magnet 2and magnet2 operates on less magnet strength than magnet 3, the wholeoperation of the apparatus shown in Fig. 2 being substantially the sameas that shown in Fig. 1.

Without limiting myself to the construction shown and described,I'claim 1. The combination with a motor having an armature, of acontrolling means therefor dcpendent for its operation upon thedifferential action of the potential and current of the motor-armature,substantially as set forth.

2. The combination with a motor having an armature, of a step-by-stepcontrolling means comprising an actuating mechanism for each stepdependent for its action upon the potential and current of themotor-armature, substantially as set forth.

3. The combination with a motor having an armature, of a step-by-stepcontrolling means comprising an actuating mechanism for each stepdependentfor its action upon the differential action of the potentialand current of the motor-armature,substantially as set forth.

4. The combination of supply-mains, a motor-armature, apotential-reducing device,and regulating means for said device connectedin series between said mains and other regulating means cooperating withthe said aforesaid regulating means, connected in a circuit in parallelwith said armature and in series with said device, substantially as setforth.

5. The combination of supply-mains, amotor-armature, apotential-reducing device,and regulating means for said device connectedin series between said mains and other regulating means cooperatingdifferentially with the aforesaid regulating means, connected in acircuit in parallel with said armature and in series with said device,substantially as set forth.

6. The combination of supply-mains, a motor armature, a resistance, andregulating means for said resistance connected in series between saidmains and other regulating means cooperating with the aforesaidregulating means, connected in a circuit in parallel with said armatureand in series with said resistance, substantially as set forth.

7. The combination of supply-mains, a motor-armature, a resistance, aregulating means for said resistance connected in series between saidmains and other regulating means cooperating differentially with theaforesaid regulating means, connected in a circuit in parallel with saidarmature and in series with said resistance, substantially as setforth.v

8. The combination with a motor having an armature, of a controllingmeans for said motor comprising an actuating-clectromagnet, saidelectromagnet having a winding depending for its energy upon thepotential of the motor-armature and another Winding dependent for itsenergy upon the current of said armature, substantially as set forth.

9. The combinationwith a motor having an armature, of a controllingmeans for said motor comprising an actuating-electromagnet, saidelectromagnet having differential Windings, one of which depends for itsenergy upon the potential of the motor-armature and another of which isdependent for its energy upon the current of said armature,substantially as set forth.

10. The combination with a motor having an armature, of a step-by-stepcontroller therefor, an electromagnet for each step, each of saidelectromagnets having differentiallywound coils, of which one dependsfor its energy upon the current and the other upon the potential of saidarmature, substantially as set forth.

11. The combination with a motor having an armature, of a resistance,supply-mains and a controller for cutting out said resistance step bystep comprising aseries of electromagnets, each of which hasdifferentially-wound coils, one of which is connected in series withsaid armature and resistance between said mains,

the other being connected in a circuit in parallel with said armatureand in series with the armature-resistance, substantially as set forth.

12. The combination with a motor having an armature, of a step-by-stepcontrolling means comprising a mechanism for each step dependent for itsoperation upon the potential and current of the motor-armature and upona mechanism of a preceding step, substantially as set forth.

13. The combination with a motor having an armature, of a step-by-stepcontrolling means comprising a mechanism for each step dependent for itsoperation upon the differential action of the potential and current ofthe motor-armature and upon a mechanism of a preceding step,substantially as set forth.

14. The combination with a motor having an armature, of a step-by-stepcontrolling means comprising an electromagnet for each step havingwindings, one of which windings depends for its energy upon the currentof the motor-armature, the other of which windings is dependent for itsenergy upon the potential of said armature, the circuits of saidwindings being controlled by an electromagnet of a preceding step,substantially as set forth.

15. The combination with a motor having an armature, of a step-by-stepcontrolling means comprising an electromagnet for each step havingdifferential windings, one of which windings depends for its energy uponthe current of the motor-armature the other of which windings isdependent for its energy upon the potential of said armature, the circuits of said windings being controlled by an electromagnet of apreceding step, substantially as set forth.

16. The combination with a motor having an armature, of a step-by-stepcontrolling means comprising a potential-reducing device, mechanism foreach step, each of said mechanisms having a coil dependent for itsenergy upon the potential of said armature, and connections whereby thesaid mechanisms successively connect the coils of succeedingmechanismsto different points of said potential-reducing device, substantially asset forth.

17. The combination with a motor having an armature, of a step-by-stepcontrolling means comprising a mechanism for each step and apotential-reducing device, each of said mechanisms having apotential-coil dependent for its energy upon the potential of saidarmature and a current-coil dependent for its energy upon the current ofsaid armature, and connections whereby the said mechanisms successivelyconnect the potential-coils of succeeding mechanisms to different pointsof said potential-reducing device, substantially as set forth.

18. The combination with a motor having an armature, of a step-by-stepcontrolling means comprising a mechanism for each step and apotential-reducing device, each of said mechanisms havingapotential-coil dependent for its energy upon the potential of saidarmature and a current-coil dependent for its energy upon the current ofsaid armature, said potential and current coils being differentiallywound, and connections whereby the said mechanisms successively connectthe potential-coils of succeeding mechanisms to different points of saidpotential-reducing device, substantially as set forth.

19. The combination with a motor having an armature, of a step-by-stepcontrolling means comprising a mechanism for each step,

' and a resistance, each of said mechanisms having a coil dependent forits energy upon the potential of said armature and connections wherebythe said mechanisms successively connect the coils of succeedingmechanisms to different points of said resistance, substantially as setforth.

2(). The combination with a motor having an armature, of a step-by-stepcontrolling & 767. 691

means comprising a mechanism for each step and a resistance, each ofsaid mechanisms having a potential-coil dependent for its energy uponthe potential of said armature and a current-coil dependent for itsenergy upon the current of said armature, and connections whereby thesaid mechanisms successively connect the potential-coils of succeedingmechanisms to different points of said resistance, substantially as setforth.

21. The combination With a motor having an armature, of a step-by-stepcontrolling means comprising a mechanism for each step and a resistance,each of said mechanisms having a potential-coil dependent for its energyscribing Witnesses.

JOHN D. IHLDER.

Witnesses: I

O. B. MANVILLE, P. WV. N EWELL.

